Process and device for punching holes in flat workpieces

ABSTRACT

To manufacture orifice disks, polygonal workpieces are prefabricated and oblique holes are punched successively by positioning the polygonal workpieces in different angular positions between lateral stops on an inclined bearing surface of a fixed punch die. The workpiece is removed after punching a hole, arranged in the following angular position and positioned between the lateral stops in order to punch the following hole. The removal and positioning of the workpiece in different angular positions is repeated to provide the required arrangement of punched holes. A device for manufacturing orifice disks includes a punch, lateral stops, and an inclined bearing surface of a fixed die. Accordingly, the series production of orifice disks of multiple-orifice nozzles for fuel-injection engines is accomplished.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a process for punching holes in flatworkpieces and a device for carrying out this process. In particular,the present invention relates to a process for manufacturing orificedisks in series for multihole fuel-injection nozzles, comprisingpunching holes successively with a single punch by stepwise angularadjustment of a sheet-metal workpiece.

2. Discussion of Background

Injection valves with orifice disks having perpendicular or obliqueholes are increasingly used in car engines and require uniformdistribution of the fuel injected into each cylinder of the engine. Theseries production of such orifice disks requires the punching ofidentical symmetrically arranged holes and is problematic inasmuch asslight deviations resulting from punching; can impair the uniformdistribution of fuel.

The series production of orifice disks for multihole nozzles for use infuel-injection engines is therefore particularly problematic inasmuch asan extremely high reproducibility of the precision of the quality andthe position of each of the holes punched with narrow spacing has to beguaranteed in order to ensure the efficient operation of fuel-injectionengines produced in large series.

SUMMARY OF THE INVENTION

The object of the invention is essentially to enable the punching ofidentical holes with relatively simple technical means in such a mannerthat the series production of such orifice plates with varioussymmetrical hole arrangements can be ensured with high precision andreproducibility to ensure the efficient operation of fuel-injectionengines.

Accord to the invention all the holes are punched with a single punch,while the workpiece is positioned successively in predetermined angularpositions and thereby respectively defines the position of each hole tobe punched in the workpiece.

The workpiece is advantageously designed in the form of a polygon whichdefines the different angular positions for positioning the workpiecewith the aid of corresponding lateral stops.

The outer form or contour of the polygonally shaped workpiece performsthe function of a template which interacts with the lateral stops in aparticularly simple manner so as to position the workpiece inpredetermined angular positions according to the invention and tothereby define the position of each hole punched in the workpiece.

The lateral stops are respectively arranged on a fixed die and adaptedto the polygonal workpiece so that they enable the selective arrangementof the workpiece in different predetermined angular positions forsuccessively punching holes in corresponding predetermined locations inthe workpiece.

Holes extending obliquely to the workpiece surface can moreover bepunched by positioning the workpiece on a bearing surface of a die whichis inclined accordingly.

Pairs of holes extending parallel to each other can moreover be punchedby providing a workpiece with two opposite sides having recesses ofdifferent depths, while the lateral stops are caused to act selectivelyon these recesses in corresponding angular positions of the workpiece.

Such pairs of holes extending parallel to each other may be punchedobliquely to the workpiece surface in a simple manner by lateraldisplacement of the polygonal workpiece with the aid of adjustable orinterchangeable stops. The symmetry of the holes punched parallel toeach other in relation to the workpiece is ensured by respectivelyrotating the workpiece to punch symmetrically arranged holes.

The device for carrying out the process according to the inventioncomprises a single punch and a fixed die with a passage for the punchand a bearing surface for the workpiece as lateral well as stops whichexclude any rotation of the polygonal workpiece while punching anddefine the different angular positions as well as the position of eachpunched hole.

As a result of the polygonal form of the workpiece according to theinvention and the predetermined angular positions in relation to thelateral stops, the coordinates of the desired holes to be punched ineach case are defined exactly in the workpiece in a simple manner tothereby ensure maximum reproducibility when punching is effected.

Different symmetrical hole arrangements may thereby be produced in avery simple manner by the stepwise angular adjustment of the workpieceaccording to the invention.

The workpiece may moreover be subsequently machined to thereby produce,for example, a circular orifice disk with the required diameter.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be explained by examples of embodiments which arerepresented schematically in the figures as follows.

FIG. 1 shows a polygonal workpiece for punching six holes according toone embodiment.

FIGS. 1a to 1f show the workpiece according to FIG. 1 in six angularpositions for successfully punching single holes.

FIG. 2 shows a vertical section of a device for carrying out the processaccording to the invention, wherein the workpiece is represented incross-section along the line II--II in FIG. 1.

FIGS. 3a to 3d show of a polygonal workpiece for punching four holesaccording to another embodiment which is represented in four angularpositions for successfully punching the individual holes.

FIGS. 4a to 4d show a variant of the embodiment according to FIGS. 3a to3d.

FIGS. 5a to 5d show a workpiece according to another embodiment forpunching pairs of parallel holes.

Similar elements have the same reference symbols in the figures.

DETAILED DESCRIPTION

The workpiece W6 in FIG. 1 consists of a twelve-sided plate with sixlong edges 11, 12, 13, 31, 32, 33 and six short sides 21, 22, 23, 41,42, 43, which are inscribed in a circle and are arranged alternately atthe periphery of the workpiece W6 in the following sequence:11-43-12-21-13-22-31-23-32-41-33-42.

FIG. 1 further shows four lateral stops A1 to A4. The stops A1, A3 andA2, A4 are arranged respectively in contact with the sides 11, 31 and21, 41 and symmetrically on perpendicular median lines X--X and Y--Ythrough the center 0 of the workpiece W6.

The stops A1 to A4 thereby define the angular position of the workpieceW6 as well as a coordinate system X-Y through the center 0 of theworkpiece W6, while the indicated coordinates x, y determine theposition of a hole 101 to be punched.

FIG. 2 shows a schematic vertical section along II--II in FIG. 1 of adevice for punching oblique holes in accordance with the invention. Thisdevice comprises a punch S1, a vertically mobile punch guide S2 with aninclined bottom surface S3, a die M1 with an inclined bearing surface M2for the workpiece W6 and a vertical passage M3 for the punch S1, as wellas the stops A2 and A4 mentioned in connection with FIG. 1. As seen fromthe figures and from the above, the punch S1 may be a vertical punch.

The bearing surface M2 of the punch die and the bottom surface S3 of thepunch guide S2 are moreover inclined at a predetermined angle inrelation to the horizontal plane, so that the workpiece W6 is inclinedat the same angle and the punched hole 101 is inclined accordingly inthe workpiece W6.

The punch guide S2 is shown in FIG. 2 in its lower position, in whichthe workpiece W6 is arranged obliquely between its bottom surface S3 andthe bearing surface M2, while the punch S1 is located in an intermediateposition.

The vertically movable punch guide is moreover connected to an adjustingdevice (not shown) whereby to bring the guide on one hand into its lowerworking position shown in FIG. 2 and on the other hand into its upperrest position which enables the workpiece to be inserted and removed.

The workpiece is on one hand positioned between the stops A1 to A4 andheld between the bearing surface M2 and the bottom surface S3 of thepunch guide S2 whereby to provide for punching a hole in the describeddevice according to FIG. 2. The punch guide S2 is on the other handbrought into its upper rest position to allow the workpiece to beinserted to provide for punching, to then be removed, rotated to thenext angular position and reinserted to punch the following hole.

The described device according to FIG. 2 serves to punch oblique holesat a predetermined angle to the workpiece, the bearing surface M2 of thedie M1 being inclined accordingly.

The described workpiece W6 in FIG. 1 serves to punch six holes which areregularly spaced distributed on a circle around the center 0 of theworkpiece W6 and their centers are designated by 101 to 106. The mannerof punching these six holes will be further described in connection withFIG. 1a to FIG. 1f.

The position of the punch S1 in relation to the workpiece and hence thecenter of the holes 101 to 106 to be punched in each case is defined bythe stops A1 to A4 at the coordinates x, y of the hole 101 representedin FIG. 1 in the coordinate system X-Y with the center lines through thecenter 0 of the workpiece W4.

The six holes 101 to 106 are is punched successively and arrangedsymmetrically as follows from FIGS. 1a to 1f.

It can be seen from the above description that, thanks to thecombination provided for in accordance with the invention of thepolygonal workpiece W6 with the lateral stops A1 to A4 and with thebearing surface M2 of the die, the workpiece is in each case positionedexactly in the required angular position for punching a given hole,whereby the coordinates x, y of each hole are definitely established andexactly aligned with the axis of the punch, so that identical holes arepunched successively in a simple manner merely by stepwise modificationof the angular position of the workpiece.

In the further embodiment according to FIGS. 3a to 3d a square workpieceW4 serves to punch four symmetrically arranged holes 301 to 304 whichare punched successively in a similar manner as already described inconnection with FIGS. 1, 1a to 1d and 2.

The following description of this arrangement is therefore simplified inorder to avoid unnecessary repetition and is limited to the differenceswith regard to the preceding description.

The workpiece W4 shown in FIGS. 3a to 3d consists of a square plate withfour sides 311, 312, 313, 314 the opposite stops A1, A3 and A2, A4 arebeing equally spaced, likewise arranged symmetrically on the centerlines X--X and Y--Y of the workpiece W4 and similarly positioning theworkpiece.

In the first angular position for punching the hole 301 the four sides311, 312, 313, 314 of the workpiece are in contact with the four stopsA1, A2, A3, A4, while the workpiece is in each case rotated by 90° tothe left to punch the four holes 301 to 304 successively as follows fromFIGS. 3a to 3d.

The described device in FIG. 2 can serve to punch in like manner thefour holes 301 to 304 in the workpiece W4, which is positioned betweenthe stops A1 to A4 on the bearing surface M2 and rotated to the left by90° in each case, while these holes are successively punched anddistributed symmetrically as follows from FIGS. 3a to 3d.

The square workpiece W4 can also serve to punch two holes in a similarway, the workpiece being rotated by 180° after punching the first hole301 in order to punch the opposite hole 303.

The variant shown in FIGS. 4a to 4d corresponds substantially to thedescribed embodiment according to FIGS. 3a to 3d, the four holes 401 to404 having in this case the coordinates x, y in the coordinate systemX-Y.

FIGS. 5a to 5d show an eight-sided workpiece W54 in four angularpositions for punching four holes arranged in pairs of holesrespectively extending parallel to each other 501, 503 and 502, 504respectively according to a further embodiment of the invention.

The workpiece W54 comprises eight sides 511 to 518 with rectangularrecesses 511b, 512b, 515b, 516b and is positioned by lateral stops A51a,A52, A53a, A54 and A51b, A52, A53b, A54 respectively in the angularpositions in FIGS. 5a, 5b and 5c, 5d, to thereby punch the holes 501 to504 successively with a single punch.

The opposite edges 511, 515 and 512, 516 of the workpiece W54 arerespectively provided with rectangular recesses of unequal depth 511b,515b and 512b, 516b which selectively interact with the correspondingstops A51a, A53a and A51b, A53b respectively according to FIGS. 5a to5d.

FIG. 5a shows the workpiece W54 in the first angular position forpunching the hole 501, the stops A51a, A52, A53a, A54 being respectivelyassociated for this purpose with the sides 511, 513, 515, 517 of theworkpiece W54 as follows: A51a/511; A52/513; A53a/515; A54/517.

FIG. 5b shows the workpiece W54 in the second angular position forpunching the hole 502, the stops A51a, A52, A53a, A54 being respectivelyassociated for this purpose with the sides 516, 518, 512, 514 of theworkpiece W54 as follows: A51a/516; A52/518; A53a/512; A54/514.

FIG. 5c shows the workpiece W54 in the third angular position forpunching the hole 503, the stops A51b, A53b being respectivelyassociated for this purpose with the rectangular recesses 511b, 515b andthe stops A52, A54 with the sides 513, 517 of the workpiece W54 asfollows: A51b/511b; A52/513; A53b/515b; A54/517.

FIG. 5d shows the workpiece W54 in the fourth angular position forpunching the hole 504, the stops A51b, A53 being respectively associatedfor this purpose with the rectangular recesses 516b, 512b and the stopsA52, A54 respectively with the sides 518, 514 of the workpiece W54 asfollows: A51b/516b; A52/518; A53b/512b; A54/514.

The stops A52 and A54 thereby serve to position the workpiece W54 in thefour described angular positions according to FIGS. 5a to 5d. Theworkpiece W54 is positioned respectively by means of the stops A51a,A53a in the first two angular positions according to FIGS. 5a and 5b forpunching the holes 501 and 502 and by of the stops A51b, A53b in the twoangular positions according to FIGS. 5c and 5d for punching the holes503 and 504.

The stops A51a, A53a are moreover replaced by the stops A51b, A53b afterpunching the first two holes 501, 502, in order to punch the next twoholes 503, 504.

The described polygonal shape of the workpiece W54 with the recesses ofunequal depth 511b, 515b and 512b , 516b respectively in combinationwith the stops A51a, A53a and A51b, A53b provides besides the differentangular adjustments in FIGS. 5a to 5d, a linear displacement of theholes 503 and 504 respectively in relation to the holes 501, 502. Inthis way the hole 503 is punched parallel to the hole 501 and the hole504 is punched parallel to the hole 502, as may be seen particularlyfrom FIG. 5d.

The process according to the invention may also be carried in other waysthan in the described embodiments, while other means may also be usedfor the stepwise angular adjustment for punching the holes successivelywith a punch in accordance with the invention.

This invention provides a special combination of advantages which may beexplained as follows:

(a) Thanks to the stepwise angular adjustment of the workpiece providedin accordance with the invention, the required holes can now be exactlypunched with the same punch and uniformly spaced in a simple manner.

(b) Oblique holes may be punched successively in like manner at a givenangle to the workpiece, the bearing surface for the workpiece beinginclined accordingly.

(c) Polygonal workpieces are in each case positioned exactly inpredetermined angular positions by corresponding late stops on thestationary die, so that the position of each hole to be punched isexactly defined on the upper side of the workpiece.

(d) Various combinations of polygonal workpieces with suitable stopsmake it possible to punch different symmetrical hole arrangements withthe same punching device.

(e) Through the combination of the polygonal workpiece withcorresponding stops, the coordinates of each hole to be punched in theworkpiece can be exactly defined in each case in a particularly simplemanner with each angular adjustment of the workpiece.

The invention is particularly adapted to the series production oforifice disks of fuel injection valves, the advantages mentioned abovebeing of special significance in this case with regard to thereproducibility in the production of such orifice disks in large series.

The punching process according to the invention is currently used forthe mass production of orifice disks for fuel injection valves with aproduction of about 10 million orifice disks per year, the followingsteps being carried out more particularly;

1. Stock verification.

2. Preparation and marking many-sided workpieces.

3. Punching holes and examination of the injection orifices.

4. Finishing and examination of the injection orifice disks.

This process may also be used for punching hole arrangements for otheruses, in order to provide similar advantages with regard to the highreproducibility which is ensured thanks to the stepwise angularadjustment using the same punch-die unit according to the invention.

I claim:
 1. A process for the mass production of orifice disks formultihole fuel-injection nozzles, comprising:prefabricating a pluralityof sheet-metal workpieces having a polygonal contour which is designedso as to define a plurality of predetermined angular positions for eachworkpiece on a stationary punch die when a given workpiece of theplurality of workpieces engages lateral stops on the stationary punchdie to determine an arrangement of oblique holes in the workpiece; andpunching a plurality of oblique holes successively in each of theplurality of workpieces having a polygonal contour with a single punchby stepwise angular adjustment of each of the plurality of workpieces inrelation to the punch:wherein each oblique hole is punched in a givenworkpiece of the plurality of workpieces by positioning the givenworkpiece in a predetermined angular position between the lateral stopsof the stationary punch die which has an inclined bearing surface, andwherein the angular adjustment of the given workpiece for punchingoblique holes successively involves removing the given workpiece fromthe stationary punch die after punching an oblique hole, rotating thegiven workpiece, and positioning the given workpiece in another angularposition for punching a further oblique hole, and wherein the removal,rotation, and positioning of the given workpiece is repeated until allthe oblique holes of a required hole arrangement have been punched suchthat the given workpiece has a plurality of oblique holes.
 2. Theprocess of claim 1, wherein the plurality of workpieces have oppositesides which respectively include recesses of unequal depth, and whereinthe stops interact with the recesses to position the given workpiece indifferent angular positions.
 3. A system for the mass production oforifice disks from a plurality of sheet-metal workpieces having apolygonal contour by stepwise angular adjustment of a given workpiece ofthe plurality of workpieces in relation to a punch, the systemcomprising:a plurality of workpieces having a polygonal contour; asingle punch; a stationary punch die having a passage for the singlepunch, an inclined bearing surface, and a set of stationary stops whichis positioned to conform with the polygonal contour of the plurality ofworkpieces, the set of stationary stops being offset in relation to thesingle punch so as to allow a given workpiece of the plurality ofworkpieces to be positioned in different predetermined angular positionsbetween the set of stationary stops on the inclined bearing surface ofthe stationary punch die and to thereby allow a plurality of obliqueholes to be punched successively in the given workpiece such that thegiven workpiece has a plurality of oblique holes, with the position ofthe oblique holes being determined by the contour of the givenworkpiece; and wherein each of the plurality of workpieces has oppositesides which respectively include recesses of unequal depth, and whereinthe set of stationary stops is positioned to be capable of interactingwith the recesses to position each of the plurality of workpieces indifferent angular positions.
 4. A punching device for the massproduction of orifice disks from a plurality of sheet-metal workpieceshaving a predetermined polygonal contour by stepwise angular adjustmentof a given workpiece of the plurality of workpieces in relation to asingle punch, comprising:a single punch; and a stationary punch diehaving a single passage vertically aligned with the single punch, thestationary punch die having an inclined bearing surface and a set ofspaced lateral stops fixed to the inclined surface of the punch die, thestops being offset such that the given workpiece may be positionedbetween the stops in different angular positions in relation to thesingle punch when different sides of the given workpiece aresuccessively positioned in contact with each stop, to allow successivepunching of oblique holes in a given arrangement in the given workpiecewhen the given workpiece is positioned on the inclined bearing surfacein the different angular positions in relation to the single punch.